Air Pollution from Combustion Sources

From Thermal-FluidsPedia

Two of the main consequences of the second law of thermodynamics that must be taken into account when burning fossil fuels are the release of large amounts of waste heat and the emission of toxic pollutants into the surrounding air and water. Thermal pollution arises because the full energy content of the fuel cannot be converted to useful work and electricity. Physical constraints are produced because the combustion process cannot go entirely to completion.

Environmental pollution does not only affect human health, but also endangers plant and animal life, damages materials, affects visibility, and contaminates air, water, and soil. These effects cost billions of dollars in cleaning, repair, replacement, prevention, and lost productivity. According to the World Health Organization (WHO), an estimated 1.5-6 million people die of air pollution related diseases annually, mostly in developing countries where health care facilities are often inadequate, environmental laws are seldom enforced, and the high costs of air pollution control equipment are largely prohibitive.

In thermal energy, we discussed the laws of thermodynamics and how they can be used to design power plants and other useful devices. In these devices, either heat is used to produce shaft work (automobile) and electricity (power plants), or work is used to move heat from a colder to a hotter space (refrigerators and heat pumps). In all cases, some heat must be discarded into the atmosphere in a process known as thermal pollution. Thermal pollution is not limited to mechanical devices, however. Any human activity, even the simple act of breathing, involves the dissipation of a substantial amount of heat to the surrounding air. Other phenomena attributed to emissions from combustion sources are smog formation, ozone depletion, and acid rain.